Advanced condition monitoring of Pelton turbines

Abstract

The ability of hydropower to adapt the electricity generation to the demand is necessary to integrate wind and solar energy into the electrical grid. Nowadays hydropower turbines are required to work under harsher operating conditions and an advanced condition monitoring to detect damage is crucial. In this paper the methodology to improve the condition monitoring of Pelton turbines is presented. First, the field data obtained from the vibration monitoring of 28 different Pelton turbines over 25 years has been studied. The main types of damage found were due to fatigue, cavitation and silt erosion. By analyzing the vibration signatures before and after maintenance tasks, the symptoms of damage detected from the measuring locations were determined for each case. Second, a physics-based model using numerical methods (FEM) was built-up in order to simulate the dynamic behavior of the turbine. The model was validated with the results obtained from on-site tests that were carried out in an existing turbine. The deformations and the stresses of the runner under different operating conditions could be then computed. The calibrated model was used to analyze in detail the effect of misalignment between nozzle and runner. In historic cases, this abnormal operating condition lead to severe damage in the turbine, due to the effect of fatigue in some locations of the buckets. The model reproduced rather well the symptoms detected in the field measurements. The stresses could be calculated which eventually can be used to estimate the remaining useful life of the turbine. *Manuscript Click here to download Manuscript: Manuscript-Pelton.pdf Click here to view linked References

Dynamic Model for Axial Motion of Horizontal Pelton Turbine and Validation in Actual Failure Case

“…For these reasons, the rotor is considered as a rigid body in axial direction. Simulations of horizontal Pelton turbines [21] show that axial natural frequencies are much higher than those of excitation forces. By international standards as API 670, the rotor should be considered as a rigid body if its main excitation frequency is below 0.7 times rotor natural frequency.…”

Bayesian network approach to fault diagnosis of a hydroelectric generation system

“…19,20 The current study of the HGS's faults mainly focuses on the constituent components (eg, generators, hydro-turbines, and pipelines). 24,25 To adequately analyze the faults mechanism, to predict behavior of systems, to evaluate operating reliability, and to decrease maintenance costs, are the challenging tasks. 24,25 To adequately analyze the faults mechanism, to predict behavior of systems, to evaluate operating reliability, and to decrease maintenance costs, are the challenging tasks.…”

“…[21][22][23] Additionally, the collection of the on-line monitoring data under the condition of fast information flow is another challenge for fault diagnosis of the HGS. 24,25 To adequately analyze the faults mechanism, to predict behavior of systems, to evaluate operating reliability, and to decrease maintenance costs, are the challenging tasks. Hence, it is of primary importance to provide the powerful methodology for the fault diagnosis of HGSs not only of systems but also of data available.…”

Detection of Hydraulic Phenomena in Francis Turbines with Different Sensors

“…Monitoring systems [11,12,13] are usually installed in hydraulic power plants with the objective of ensuring a safe operation of the machine, performing predictive maintenance and detecting possible failures [14,15,16]. Those monitoring systems are usually based on measuring vibration in the stationary parts of the machine, especially in the bearings, the shaft displacement or oil temperatures.…”